Python 操作MySQL详解及实例

时间:2022-11-06 21:23:07

Python 操作MySQL详解及实例

使用Python进行MySQL的库主要有三个,Python-MySQL(更熟悉的名字可能是MySQLdb),PyMySQL和SQLAlchemy。

Python-MySQL资格最老,核心由C语言打造,接口精炼,性能最棒,缺点是环境依赖较多,安装复杂,近两年已停止更新,只支持Python2,不支持Python3。

PyMySQL为替代Python-MySQL而生,纯python打造,接口与Python-MySQL兼容,安装方便,支持Python3。

SQLAlchemy是一个ORM框架,它并不提供底层的数据库操作,而是要借助于MySQLdb、PyMySQL等第三方库来完成,目前SQLAlchemy在Web编程领域应用广泛。

本文主要介绍PyMySQL的正确使用方法,示例代码都是选自实战项目。

安装

简单的方式:

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pip install pymysql

如果无法联网,需要进行离线安装,例如:

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pip install pymysql-x.x.x.tar.gz

导入

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import pymysql

连接

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def connect_wxremit_db():
  return pymysql.connect(host='10.123.5.28',
              port=3306,
              user='root',
              password='root1234',
              database='db_name',
              charset='latin1')

查询

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def query_country_name(cc2):
  sql_str = ("SELECT Fcountry_name_zh"
        + " FROM t_country_code"
        + " WHERE Fcountry_2code='%s'" % (cc2))
  logging.info(sql_str)
 
  con = mysql_api.connect_wxremit_db()
  cur = con.cursor()
  cur.execute(sql_str)
  rows = cur.fetchall()
  cur.close()
  con.close()
 
  assert len(rows) == 1, 'Fatal error: country_code does not exists!'
  return rows[0][0]

简单插入

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def insert_file_rec(self, file_name, file_md5):
    con = mysql_api.connect_wxremit_db()
    cur = con.cursor()
    try:
      sql_str = ("INSERT INTO t_forward_file (Ffile_name, Ffile_md5)",
            + " VALUES ('%s', '%s')" % (file_name, file_md5))
      cur.execute(sql_str)
      con.commit()
    except:
      con.rollback()
      logging.exception('Insert operation error')
      raise
    finally:
      cur.close()
      con.close()

批量插入

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remit_ids = [('1234', 'CAD'), ('5678', 'HKD')]
 
con = mysql_api.connect_wxremit_db()
    cur = con.cursor()
    try:
        cur.executemany("INSERT INTO t_order (Fremit_id, Fcur_type, Fcreate_time"
                        + " VALUES (%s, %s, now())", new_items)
        assert cur.rowcount == len(remit_ids), 'my error message'
        con.commit()
    except Exception as e:
        con.rollback()
        logging.exception('Insert operation error')
    finally:
        cur.close()
        con.close()

更新

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def update_refund_trans(self, remit_id):
   con = mysql_api.connect_wxremit_db()
   cur = con.cursor()
   try:
     sql_str = ("SELECT Fremit_id"
           + " FROM t_wxrefund_trans"
           + " WHERE Fremit_id='%s'" % remit_id
           + " FOR UPDATE")
     logging.info(sql_str)
 
     cur.execute(sql_str)
     assert cur.rowcount == 1, 'Fatal error: The wx-refund record be deleted!'
 
     sql_str = ("UPDATE t_wxrefund_trans"
           + " SET Fcheck_amount_flag=1"
           + ", Fmodify_time=now()"
           + " WHERE Fremit_id='%s'" % remit_id
     logging.info(sql_str)
     cur.execute(sql_str)
 
     assert cur.rowcount == 1, 'The number of affected rows not equal to 1'
     con.commit()
   except:
     con.rollback()
     logging.exception('Update operation error')
     raise
   finally:
     cur.close()
     con.close()

PyMySQL已经相当成熟,和Python-MySQL一样,它在很多Linux发行版本中都是可选的安装组件。

感谢阅读,希望能帮助到大家,谢谢大家对本站的支持!

原文链接:https://www.qcloud.com/community/article/687813